<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box{
            position: relative;
            width: 300px;
            height: 100px;
            margin: 50px auto;
            background-color: pink;
        }
        .x::before{
            content: "";
            position: absolute;
            left: -16px; 
            top: 20px;
            width: 0px;
            height: 0px;
            border: 10px solid transparent;
            border-right-color: pink;
        }
        .x::after{
            content: "";
            position: absolute;
            right: -16px; 
            top: 20px;
            width: 0px;
            height: 0px;
            border: 10px solid transparent;
            border-left-color: pink;
        }
    </style>
</head>
<body>
    <div class="box">
       <div class="x"></div>
       <video controls="" autoplay="" name="media">
           <source src="https://m8.music.126.net/20210329215258/40e6a33c0c5c494ea1a875ed880fc73c/ymusic/obj/w5zDlMODwrDDiGjCn8Ky/8126459184/2a54/c224/1f26/d4aabb612653df02d57748e7f64e2de1.mp3" type="audio/mpeg">
       </video>

        <video  style="width: 550px;" src="https://cdn.mphot.cn/video/bg_video.mp4"></video>

    </div>
</body>
</html>